Part B Listening Comprehension Directions: In this part of the test there will be some short talks and conversations. After each one, you will be asked some questions. The talks, conversations and questions will be spoken ONLY ONCE. Now listen carefully and choose the right answer to each question you have heard and write the letter of the answer you have chosen in the corresponding space in your ANSWER BOOKLET. 听力原文：Woman: Tell us more about this 'Mars Underground.' Who are they, what have they been doing? Man: Well, they're several dozen scientists and engineers, some of them work at NASA, um, a lot of them work at universities, or space contractors, and these are people who just believe that it's humankind's destiny to go to Mars—er, a little bit for economic reasons, a little bit for political reasons, but really, for, you know, the same romantic reasons that sent us exploring in any other century—and they have been quietly—quietly, really, because no one has been interested—paying attention to some of the results from the unmanned missions that we have been sending to Mars for more than twenty years— and keeping an eye on which discoveries might be relevant to getting humans to Mars, to letting them explore around there for a long time, and even, one day, setting up colonies there. Woman: So the $64 billion question is always what can humans do going to Mars that the machines we've already sent can't? Man: Well, and that question has been raised by the, em, claim of life on Mars. And the answer is if there is life on Mars, it's not, you know, standing on the tarmac waiting to say: here we are! Em, it's underground. And a robot is not good at digging underground, nor at looking at, er, what are the most promising sites. Em, so that's the current motivation for sending astronauts to Mars. You know, not next week, but sometime, um, in the next decade. Woman: Last question for you—Where will scientists focus their search for life, past or present? Man: There are a lot of interesting places. Most of them have to do with water and energy again, if there was life, it needed liquid water, and it needed a source of energy. There are dry lake beds, there are dry river channels, there are places where there may be thermal system, kind of like Yellowstone National Park, springs and fumeroles, and if there is or was life there, that's where you would look certainly for the fossils, and maybe even for some survivors. Woman: Thanks a lot. Questions: 1.According to the interview, what is the Mars Underground? 2.According to the interview, what are members of the Mars Underground doing? 3.According to the interview, why should we send humans instead of robots to Mars? 4.According to the interview, which of the following statements is true? 5.Scientists will focus their search for life on a lot of interesting places. According to the interview, which of the following is definitely not one of them? (21)